Supersonic aircraft are designed to operate at predetermined design conditions, such as a design-condition weight and a design-condition speed, to name just two. When the supersonic aircraft is operated at the design-conditions, the supersonic aircraft will have a corresponding shape (the “design shape”). The design shape will give rise to a corresponding volume and lift distributions along the supersonic aircraft. If the shape of the supersonic aircraft changes, so will the lift distribution.
The magnitude of the sonic boom (e.g., the perceived loudness at ground level caused by passage of the supersonic aircraft overhead at supersonic speeds) generated by the supersonic aircraft correlates strongly with the volume and lift distributions. By extension, the magnitude of the sonic boom also correlates with the shape of the supersonic aircraft. When designers calculate the magnitude of the sonic boom caused by the supersonic aircraft during supersonic flight, these calculations are based on the design shape.
During the flight of a supersonic aircraft, its shape will deviate from the design shape because its conditions will change. For instance, when the aircraft takes off, it may be carrying an amount of fuel that causes the supersonic aircraft to exceed its design-condition weight. During the flight, the supersonic aircraft may fly at supersonic speeds that are both above and below the design-condition speed. During the flight, the supersonic aircraft will consume fuel such that by the end of the flight, the supersonic aircraft may weigh less than its design-condition weight.
Exceeding the design-condition weight and/or design-condition speed can cause the wings of the supersonic aircraft to deflect upwards beyond a design-condition orientation. Similarly, operating the supersonic aircraft below the design-condition weight and/or speed can cause the wings to deflect downward beyond the design-condition orientation. Furthermore, the wings on a supersonic aircraft are typically swept back to reduce drag. When a swept wing deflects up or down, it causes the wing to twist because of the wing's restrained condition at the fuselage and its unrestrained condition at the wing tip. Wing twist increases in magnitude in the outboard direction and is most pronounced at the wing tip. As a swept wing deflects in an upward direction, the wing will twist in a nose-down direction. As a swept wing deflects in a downward direction, the wing will twist in a nose-up direction.
Changes in the shape of the supersonic aircraft, and in particular, changes in the amount of twist that a wing experiences will cause the lift distribution on the supersonic aircraft to vary from the desired lift distribution. This can negatively impact the magnitude of the sonic boom generated by the supersonic aircraft. It is desirable to control the magnitude of the sonic boom, and therefore it is desirable to control changes in the shape and lift distribution of the supersonic aircraft during the supersonic portions of its flight.
Accordingly, it is desirable to provide systems that can counteract the forces that cause the wings to twist and that cause the lift distribution along the supersonic aircraft to vary. In addition, it is desirable to provide methods to counteract wing twist and variations in the lift distribution. Furthermore, other desirable features and characteristics will become apparent from the subsequent summary and detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.